CAIRO, Jan. 26 -- Alaa and Gamal, the two sons of ousted Egyptian president Hosni Mubarak, have been released from prison, official MENA news agency reported on Monday.

"The Prison Sector has released Gamal and Alaa, the two sons of the former president in the corruption case of the presidential palaces," a security source was quoted by MENA as saying.

The source added that Alaa and Gamal were released late on Sunday according to a court ruling last week.

On Thursday, the Cairo Criminal Court ordered the release of the two sons pending the case of the presidential palaces, in which they, along with their father, were accused of embezzling public funds earmarked for the renovation of the palaces.

Last May, the court sentenced Mubarak to three years and his two sons to four years in the case.

On Jan. 13, the Cassation Court annulled their conviction and ordered a retrial.

The Mubaraks have spent nearly four years in prison since they were arrested in April 2011 after the Jan. 25 uprising that ousted long-time ruler Mubarak.

The two sons still face trial on insider trading. They had been acquitted of other charges.

Mubarak, in addition to the embezzlement case, had also been facing other charges, including complicity in the killing of protesters in 2011.

Last November, the Cairo Criminal Court dismissed the killings charges against the 86-year-old Mubarak, his interior minister, and six senior security officials.

Mubarak is still staying at Maadi Military Hospital in southern Cairo, but his lawyer said he should be freed in the presidential palaces' case as he already had served more than three years.